package com.xuecheng.framework.exception;

// 统一异常捕获类

import com.google.common.collect.ImmutableMap;
import com.xuecheng.framework.model.response.CommonCode;
import com.xuecheng.framework.model.response.ResponseResult;
import com.xuecheng.framework.model.response.ResultCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

@ControllerAdvice       //控制器增强
public class ExceptionCatch {

    // 记录日志
    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionCatch.class);

    // 定义map, 配置异常类型所对应的错误代码,    Class<? extends Throwable>表示异常类型
    private static ImmutableMap<Class<? extends Throwable>, ResultCode> EXCEPTIONS;
    // 定义map的builder对象, 去构建ImmutableMap, 用静态方法模块构建
    protected static ImmutableMap.Builder<Class<? extends Throwable>,ResultCode> builder = ImmutableMap.builder();



    // 捕获CustomExceptino此类异常. @ExceptionHandler:异常处理的注解, 凡是碰到CustomException这类异常就统一捕获
    @ExceptionHandler(CustomException.class)    // 指定捕获那一类异常
    @ResponseBody
    public ResponseResult customException(CustomException customException){
        // 记录日志
        LOGGER.error("catch exception:{}", customException.getMessage());
        ResultCode resultCode = customException.getResultCode();
        return new ResponseResult(resultCode);
    }

    // 捕获Exception此类异常
    @ExceptionHandler(Exception.class)    // 指定捕获那一类异常
    @ResponseBody                         // 将异常信息捕获到, 转为json再输出到客户端
    public ResponseResult exception(Exception exception){
        // 记录日志
        LOGGER.error("catch exception:{}", exception.getMessage());
        if (EXCEPTIONS == null){
            EXCEPTIONS = builder.build();
        }
        // 从EXCEPTIONS中找异常类型所对应的错误代码，如果找到了将错误代码响应给用户，如果找不到给用户响应99999异常
        ResultCode resultCode=EXCEPTIONS.get(exception.getClass());
        if (resultCode != null){
            return new ResponseResult(resultCode);
        }else{
            // 返回99999异常
            return new ResponseResult(CommonCode.SERVER_ERROR);
        }
    }

    static {
        // 定义异常类型所对应的错误代码
        builder.put(HttpMessageNotReadableException.class,CommonCode.INVALID_PARAM);
    }



}
